I mated the two previous pics together for color reference, providing a comparison of a peacock blue Natco to a cobalt blue Natco. The peacock blue Natco pictured to the left is a medium glowing shade--they do come in deeper, darker shades. The single listing of 'cobalt blue' was added to the price guide when the actual example pictured above was first reported to the hobby. They are extremely scarce, with just a very small number known (probably less than 4-5 in damaged to good condition).